EP0302178A2 - Senseur de position - Google Patents

Senseur de position Download PDF

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Publication number
EP0302178A2
EP0302178A2 EP88105743A EP88105743A EP0302178A2 EP 0302178 A2 EP0302178 A2 EP 0302178A2 EP 88105743 A EP88105743 A EP 88105743A EP 88105743 A EP88105743 A EP 88105743A EP 0302178 A2 EP0302178 A2 EP 0302178A2
Authority
EP
European Patent Office
Prior art keywords
objects
wavelength
light
filter
wafer
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP88105743A
Other languages
German (de)
English (en)
Other versions
EP0302178A3 (en
EP0302178B1 (fr
Inventor
Tsutomu Miyatake
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sumitomo Heavy Industries Ltd
Original Assignee
Sumitomo Heavy Industries Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sumitomo Heavy Industries Ltd filed Critical Sumitomo Heavy Industries Ltd
Publication of EP0302178A2 publication Critical patent/EP0302178A2/fr
Publication of EP0302178A3 publication Critical patent/EP0302178A3/en
Application granted granted Critical
Publication of EP0302178B1 publication Critical patent/EP0302178B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
    • G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
    • G03F9/7003—Alignment type or strategy, e.g. leveling, global alignment
    • G03F9/7023—Aligning or positioning in direction perpendicular to substrate surface
    • G03F9/7026—Focusing

Definitions

  • This invention relates to an apparatus for accurately sensing the positions of two articles separated from each other by a very short distance.
  • the gap between the two objects must be made small in order to improve resolution.
  • the settable gap is on the order of 10 microns, resolution must be reduced, thus making it impossible to detect the clear image necessary for highly accurate alignment.
  • the first is a detecting optical system that relies upon a double focal point lens utilizing the principle of birefringence (see “X-Ray Exposure Devices” in Precision Machines . 1985, vol. 51, No. 12, pp. 34 - 38).
  • the second is a detecting optical system using rhombic detection (see the specifica­tion of Japanese Patent Application Laid-Open No. 61-100930).
  • Focal depth ⁇ /2n(1 - cos ⁇ ) (2) where ⁇ : wavelength used, NA: numerical aperture, n : refractive index of medium, ⁇ : angular aperture.
  • the required focal depth would be 10 ⁇ m or more. Accordingly, from Eq. (1), resolving power would be less than 1.1 ⁇ m in such case.
  • the alignment marks of the mask and wafer be sensed with greater clarity by raising the resolving power of the objective lens in the detecting optical system.
  • the focal depth must be increased in order to set the gap between the mask and wafer to a usable range (no less than about 10 ⁇ m). It is obvious from Eqs. (1) and (2), however, that both of these requirements cannot be satisfied simultaneously.
  • an object of the present invention is to provide an apparatus for sensing the positions of two spaced objects, wherein it is possible to obtain a depth of focus greater than a settable gap between the two objects upon assuring a sufficient resolving power for, e.g., highly precise alignment, while resolving power and focal depth abide by the foregoing Rayleigh equations.
  • the foregoing object is attained by providing an apparatus for sensing the positions of first and second objects separated from each other by a very small distance, comprising a lens system designed in accordance with the distance between the first and second objects and visible light having first and second suitably set wavelengths for imaging, in an identical plane, a mark of the first object by the visible light of the first wavelength and a mark of the second object by the visible light of the second wavelength; a filter for cancelling light other than the light for imaging, the filter conform­ing to the shapes or the positions of the respective imaged marks of the first and second objects; and a processing system for processing images passed by the filter and indicating a positional relationship between the first and second objects.
  • an objective lens is accompanied by other lenses such as an eyepiece and relay lens to provide an image having a certain magnification.
  • other lenses such as an eyepiece and relay lens to provide an image having a certain magnification.
  • the discussion will be limited solely to a single objective lens.
  • a thin lens system will be dealt with and only paraxial formulae will be used.
  • Fig. 1 illustrates the initial settings for the aforementioned conditions (1) through (4).
  • the lens position is referred to as the principal point, and this position is shown at A on the optic axis.
  • the object is situated on the left side of the lens at a position M located at a distance S from the principal point. Images for the respective wavelengths can be formed at points B and C on the side of the lens opposite the object.
  • the refractive index of the objective lens differs depending upon the wavelength; the shorter the wavelength, the higher the refractive index and, hence, the closer the focal point is to the lens. Accordingly, since the wave­lengths are related by ⁇ ⁇ ⁇ , the image for wavelength ⁇ is formed at point B, and the image for wavelength ⁇ is formed at point C.
  • S ⁇ ⁇ , S ⁇ ⁇ represent the distances of the respective images from the principal point.
  • Fig. 2 shows the result of such move­ment, with the new object position being designated M′.
  • Fig. 3 differs from Figs. 1 and 2 in that a new point D appears on the left side of point B. This point is that at which the image of the wafer (point M′) is formed for wavelength ⁇ Letting Sd represent the distance of this point from the principal point A, we find Sd as follows:
  • Fig. 4 Examples of the alignment marks for a mask and wafer are as shown in Fig. 4, in which the alignment marks are imagined to be rectangular and the shorter side of the mask mark is assumed to be greater than the shorter side of the wafer mark.
  • Fig. 5 With the mask and wafer of Fig. 4 superimposed, the patterns which appear on the picture tube screen along with blurring caused by chromatic aberration are illustrated in Fig. 5.
  • the color associated with wavelength ⁇ is indicated by the solid lines, and the color associated with wavelength ⁇ is indicated by the broken lines.
  • chromatic aberration of magnification The blurring due to chromatic aberration in Fig. 5 is referred to as chromatic aberration of magnification.
  • the chromatic aberrations of magnification associated with the mask and wafer shall be denoted by Zm and Zw and are obtained by using the following equations: where h represents the length of the long side of the rectangular marks.
  • the blurring expressed by Eqs. (6) and (7) is determined geometrically in Fig. 3.
  • a filter of the kind shown in Fig. 6 may be used to remove the blurred portions of Fig. 5.
  • the filter illus­trated in Fig. 6 is composed of two coated surfaces. One is a coated surface which passes only the light of wavelength ⁇ , while the other is a coated surface which passes only the light of wavelength ⁇ .
  • the design of the filter is decided in accordance with the state of the patterns shown in Fig. 5, and the boundaries of the coated surfaces are situ­ated intermediate those of the mask marks and wafer marks.
  • Magnification error is a factor which must be taken into consideration in terms of processing the images picked up by a detecting system based on this chromatic aberration. Since reduction takes place owing to the magnification of 9.792X with regard to the wafer in the calculations exempli­fied above, it is required that the scaling constant for the wafer be reduced at a ratio of 10:9.792 for a mask magnifi­cation of 10X. As for the filter, design should conform to the shapes or positions of the alignment masks.
  • the overall arrangement of a lens system is illus­trated in Fig. 7, in which a relay lens, field lens and objective lens are used in combination.
  • the most important lens is the objective lens which, in the illustrated embodiment, is basically designed based on the system described in the specification of Japanese Patent Publica­tion No. 43-15237.
  • the present lens system is designed so as to employ two types of light beams, namely a g line (wavelength: 435.84 nm) and e line (wavelength: 546.07 nm).
  • the objective lens specifications are shown in Table 2.
  • Fig. 8 illustrates the aberration curves. These curves also clearly show that the aberrations are well corrected.
  • the objective lens specifications are shown in Table 6.
  • Fig. 9 illustrates the aberrations curves. These curves also show that the aberrations are well corrected.
  • the objective lens specifications are shown in Table 9.
  • Fig. 10 illustrates the aberration curves. These curves also show that the aberrations are well corrected.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Lenses (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
  • Automatic Focus Adjustment (AREA)
  • Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
  • Length Measuring Devices By Optical Means (AREA)
EP88105743A 1987-08-07 1988-04-11 Senseur de position Expired - Lifetime EP0302178B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP196174/87 1987-08-07
JP62196174A JPS6441805A (en) 1987-08-07 1987-08-07 Position detecting apparatus of two bodies, which are separated by minute distance

Publications (3)

Publication Number Publication Date
EP0302178A2 true EP0302178A2 (fr) 1989-02-08
EP0302178A3 EP0302178A3 (en) 1989-11-23
EP0302178B1 EP0302178B1 (fr) 1994-03-16

Family

ID=16353429

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88105743A Expired - Lifetime EP0302178B1 (fr) 1987-08-07 1988-04-11 Senseur de position

Country Status (4)

Country Link
US (1) US4918301A (fr)
EP (1) EP0302178B1 (fr)
JP (1) JPS6441805A (fr)
DE (1) DE3888423T2 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0411966A3 (en) * 1989-08-04 1991-04-17 Canon Kabushiki Kaisha Position detection method and apparatus
EP0385272A3 (fr) * 1989-02-27 1991-08-28 Sumitomo Heavy Industries Co., Ltd. Détecteur à double focalisation utilisant l'aberration chromatique
EP0408381A3 (en) * 1989-07-13 1992-07-01 Matsushita Electric Industrial Co., Ltd. Position signal producing apparatus
WO2008073710A1 (fr) * 2006-12-12 2008-06-19 Evident Technologies Système pour la reconnaissance d'un signal optique et matériaux à utiliser dans un tel système
US7777870B2 (en) 2006-12-12 2010-08-17 Evident Technologies, Inc. Method and system for the recognition of an optical signal

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0355496A3 (fr) * 1988-08-15 1990-10-10 Sumitomo Heavy Industries Co., Ltd. Détecteur de position utilisant une plaque de zones fresnel sectorielle
DE68923802T2 (de) * 1989-12-28 1995-12-07 Sumitomo Heavy Industries Verfahren zur beleuchtung mit zusammengesetzten farben sowie beleuchtung in vorgegebener wellenlänge in einem doppelfokusdetektor unter verwendung chromatischer aberration.
US8879058B2 (en) * 2010-11-05 2014-11-04 The University Of Ottawa Miniaturized multimodal cars endoscope
JP2012216728A (ja) * 2011-04-01 2012-11-08 V Technology Co Ltd 露光装置のアライメント装置
JP5747306B2 (ja) * 2011-05-23 2015-07-15 株式会社ブイ・テクノロジー 露光装置のアライメント装置

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5635066B2 (fr) * 1973-09-06 1981-08-14
US3990798A (en) * 1975-03-07 1976-11-09 Bell Telephone Laboratories, Incorporated Method and apparatus for aligning mask and wafer
JPS6042725A (ja) * 1983-08-18 1985-03-07 Olympus Optical Co Ltd 焦点検出装置
US4650983A (en) * 1983-11-07 1987-03-17 Nippon Kogaku K. K. Focusing apparatus for projection optical system
DE3413374A1 (de) * 1984-04-10 1985-10-17 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Optisches justierverfahren
US4734570A (en) * 1985-11-20 1988-03-29 Olympus Optical Co., Ltd. Active focus detecting device with infrared source
JP2614843B2 (ja) * 1985-12-02 1997-05-28 オリンパス光学工業株式会社 自動焦点顕微鏡
JP2797250B2 (ja) * 1987-05-14 1998-09-17 株式会社ニコン 投影露光装置

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0385272A3 (fr) * 1989-02-27 1991-08-28 Sumitomo Heavy Industries Co., Ltd. Détecteur à double focalisation utilisant l'aberration chromatique
EP0408381A3 (en) * 1989-07-13 1992-07-01 Matsushita Electric Industrial Co., Ltd. Position signal producing apparatus
EP0411966A3 (en) * 1989-08-04 1991-04-17 Canon Kabushiki Kaisha Position detection method and apparatus
US5114236A (en) * 1989-08-04 1992-05-19 Canon Kabushiki Kaisha Position detection method and apparatus
WO2008073710A1 (fr) * 2006-12-12 2008-06-19 Evident Technologies Système pour la reconnaissance d'un signal optique et matériaux à utiliser dans un tel système
US7777870B2 (en) 2006-12-12 2010-08-17 Evident Technologies, Inc. Method and system for the recognition of an optical signal
US7804587B2 (en) 2006-12-12 2010-09-28 Evident Technologies, Inc. System for the recognition of an optical signal and materials for use in such a system

Also Published As

Publication number Publication date
EP0302178A3 (en) 1989-11-23
US4918301A (en) 1990-04-17
JPS6441805A (en) 1989-02-14
JPH054601B2 (fr) 1993-01-20
EP0302178B1 (fr) 1994-03-16
DE3888423D1 (de) 1994-04-21
DE3888423T2 (de) 1994-10-27

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